The "Forward, my nobel jackals" story is a story written in the Decades of darkness universe it´s presented as an ATL story within said universe, diverging by longer live of Thomas Jefferson and no-repeal of the embargo- act. (ye It´s bloody confusing

). The story is identical to the history of the world you the reader lives in.( you know Abraham Lincoln, Roosevelt, Stalin, Hitler). Now offer your opinion from the perspective of a person living in the Decades of darkness universe.
IC: Okay, I'll start.
Let me just say.....wow. My uncle Patrick remembers when this trilogy first came out in 1976. I was only 6 then, and didn't actually buy the series until 1988, after I graduated high school, but I've been in love with the 'Verse ever since(also, this series is called "America the Beautiful here in the U.S.).
You may have noticed, that there's no New England and that slavery ended in 1865 ITTL instead of 1966-67 as per OTL(and with a lot less violence & bloodshed, too.). That was one of the parts that really stood. And the banning of marijuana in 1938 reminds me quite well of what almost happened in 1935 IOTL; had it not been for North California, Oregon, Illinois, and Louisiana voting no, and mainly thanks to massive amounts of Progressive outcry. the Caden-Portman Act would have passed; there was a huge amount of support for this law from the tobacco and booze industries as well as the reactionary hardcore racist right, including many Vitalists.
The only major difference here is that at least in the Caden-Portman Act, industrial hemp would still have been legal; ITTL's law didn't even have that provision.
Hitler, btw, reminded me quite eerily of Jefferson Davis Caden in some ways, particularly in the way he despised Jews, Poles, and Gypsies(or Roma).....in the same general fashion Caden began to truly hate Mexicans, Poles, Japanese(they don't call their country "Nippon" anymore), Liberians, etc., after his 1932 loss to Alvar O'Brien. Only difference is, Hitler won his election and died in his bunker; Caden was assassinated, quite brutally, in fact, by a leftist guerilla.
I also liked how the author went into depth covering the 1960s; the summer of 1967, in particular, was referred to as the "Summer of Love".......sadly, it had a totally different meaning IOTL(my aunt Diane was one of the tens of thousands of people who died due to the violence that summer. She was only 18, too.

).
And then, there's so much other good stuff, it'd take so many hours to cover it all.....
All in all, this is definitely in the range of a 1 on the Allo-Historical Plausibility Scale. Well written, unique, and there may never be another like it.....
OOC: Perhaps I'll write a more succinct summary at some point, but hopefully, this'll do OK for now.